As a related-art laminated header, there is known a laminated header including a first plate-like body having a plurality of outlet flow passages formed therein, and a second plate-like body laminated on the first plate-like body and having a distribution flow passage formed therein so as to distribute refrigerant, which passes through an inlet flow passage to flow into the second plate-like body, to the plurality of outlet flow passages formed in the first plate-like body to cause the refrigerant to flow out from the second plate-like body. The distribution flow passage includes a branching flow passage having a plurality of grooves extending radially in a direction perpendicular to a refrigerant inflow direction. The refrigerant passing through the inlet flow passage to flow into the branching flow passage passes through the plurality of grooves to be branched into a plurality of flows, to thereby pass through the plurality of outlet flow passages formed in the first plate-like body to flow out from the first plate-like body (for example, see Patent Literature 1).